A wind turbine known in the art comprises a tapered wind turbine tower and a wind turbine nacelle positioned on top of the tower. A wind turbine rotor with a number of wind turbine blades is connected to the nacelle through a low speed shaft, which extends out of the nacelle front.
As large modern wind turbines get bigger and bigger both in power output and in cost the issue of downtime becomes more and more significant and modern wind turbines are constantly improved to ensure that they are able to produce power efficiently whenever usable wind conditions are present.
However, icing of the wind turbine blades can be a big problem in that it can prevent the wind turbine from producing power even though ideal wind conditions are present. From U.S. Pat. No. 6,890,152 it is known to provide the blades of a wind turbine with a number of sonic horns, which will make the blades vibrating when being activated and thereby make the ice break off. The disadvantages of such a system are unfortunately many, noise problems, cost, difficult to implement in the blades etc.
Further known solutions comprise passive coating of the blades and active heating panels. Currently no coating is available that lasts more than a couple of years and the heating panels require apart from the panels wiring and this reduces the aerodynamic efficiency of the blade as well as it causes problems as regards lightning.